Added velocity and wavelenth axis to ppxf plots
Fixed issues with plotting wavelength in stellarFit
Smooth out the mased regions in the call to ppxf.

"Smoothed out" means that the regions that are masked are expanded a bit
with a gaussian smoothing filter.
Changed stellarFit to use non-normalized input files.

The thought is to let the polynomial fits in ppxf deal with the
normalization.